The dynamics of oil-in-water emulsion droplet formation in a coaxial micro-channel was investigated by using a numerical method based on VOF/CSF models. Two typical flow regimes in droplet formation process under different flow conditions, namely dripping and jetting, were simulated by the numerical method, which were in good agreement with the results of experiments. Further, the effect of velocities, viscosities and interfacial tension of continuous and dispersed phases on the lengths of droplet liquid thread and column were studied separately. With increasing the velocities and viscosities of continuous and dispersed phase or decreasing the interfacial tension, the liquid thread becomes increased apparently, ultimately leading to form the satellite droplets and reducing the emulsion monodispersity. Moreover, it was found that only with the increase of dispersed phase velocity, the liquid column becomes longer obviously which indicates that the transition from dipping to jetting mode occurs. Compared to traditional water-in-oil emulsion, oil-in-water droplet formation in dripping flow regime can be operated at much higher velocity of continuous phase, which is in advantage of producing monodispers droplets faster. The research results provide a useful guide for the preparation of monodisperse droplet with controllable size by using the coaxial microfluidic device.

Numerical study of the dynamics of oil-in-water droplet formation in a coaxial micro-channel

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.